1. Open API's, good documentation and community engagement goes a long way in establishing developer trust. I don't believe developer trust is correlated significantly with revenue (directly), but it's absolutely correlated with acquisition. I'd argue that Angular or React were partially successful because of the stickiness of their communities, and that's a powerful self-perpetuating force.
2. Monetization is in the queries. Facebook and Google know this. Throwing aside all of their auxiliary services, emerging markets, hardware, et al... between 70-90% of their respective revenue is from direct advertising. If there's a way to scale or "ramp" their revenue model, this would be the portion to focus on.